Method and device for holding and releasing a cable in a pipe splitter

ABSTRACT

A cable retention and release mechanism includes a cable gripping device including a cable passage. A cable extends through the cable passage. A cable gripping device collar is movably coupled around the cable gripping device. An outer cable gripping device surface is seated against a cable gripping device receiving inner surface preventing movement of the cable gripping device relative to the cable gripping device collar. The cable gripping device receiving inner surface clamps the cable gripping device on the cable and prevents sliding movement of the cable. A jack is movably coupled with the cable gripping device collar. In a first engaged position the jack is engaged against the cable gripping device proximal end. In a second engaged position the jack unseats the outer cable gripping device surface from the cable gripping device receiving inner surface and releases the clamping of the cable.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/599,925, filed on May 19, 2017, which is a continuation of U.S.patent application Ser. No. 15/225,229, filed on Aug. 1, 2016, which isa continuation of U.S. patent application Ser. No. 14/309,345, filed onJun. 19, 2014, which is a continuation of U.S. patent application Ser.No. 13/857,251, filed on Apr. 5, 2013, which is a continuation of U.S.patent application Ser. No. 12/686,229, filed on Jan. 12, 2010, whichclaims the benefit of U.S. Provisional Patent Application Ser. No.61/144,064, filed Jan. 12, 2009, the benefit of priority of each ofwhich is claimed hereby, and each of which is incorporated by referenceherein in its entirety.

TECHNICAL FIELD

This invention relates to devices and methods for pulling a flexibleSpecifically, this invention relates to cable pulling devices, methods,and accessories for pipe replacement.

BACKGROUND

Pipe, such as plastic, copper, lead pipe and the like, has been used forconnecting homes and creating networks for utilities, for instance,water, sewage and natural gas. As pipes become older, they break down,crack, develop scaling on interior surfaces that can clog the pipe, etc.and thereby require replacement.

A technique know as pipe bursting is currently used as a convenientmethod to replace underground pipe without the need to completely dig upthe pipe to be replaced. A pipe breaking device, such as an expander ora mole, is pulled by a cable on a motorized spool through the existingpipe while it is still underground. The expander is designed to break,split or burst the pipe, and at the same time to push the old pipe intothe surrounding soil. The expansion of the old pipe allows the theexpander to pull a replacement pipe into place.

After use, the pipe breaking device may be decoupled from the cable toallow threading of the cable through another existing pipe or to storethe cable on the spool until needed in the future. The cable pulling thepipe breaking device is often tightly coupled with the cable due to thepulling forces of the motorized spool. Because of the flexible nature ofthe cable it can be very difficult to decouple the cable from the pipesplitter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A Is a side view of one example of an above-ground pipe burstingand pulling system using a portable motorized puller.

FIG. 1B Is a side view of one example of an in-ground pipe bursting andpulling system using a portable motorized puller.

FIG. 2A Is a perspective view of one example of a pipe splittingassembly including a cable locking assembly.

FIG. 2B Is a cross-sectional view of the pipe splitting assembly shownin FIG. 2A,

FIG. 3 Is a perspective view of one example of a cable gripping device.

FIG. 4 Is a perspective view of one example of a jack.

FIG. 5 Is a perspective view of one example of a cable gripping devicecollar.

FIG. 6 Is a cross-sectional view of the pipe splitting assemblyincluding one example of a cable locking assembly where the cablegripping device is locked with the cable gripping device collar andimmobilizes the cable relative to the pipe splitting assembly,

FIG. 7 Is a cross-sectional view of the pipe splitting assemblyincluding one example of a cable locking assembly where the cablegripping device is disengaged from the cable gripping device collar bydistal movement of the jack.

FIG. 8 Is a block diagram showing one example of a method of releasingthe cable locking assembly.

FIG. 9 Is a block diagram showing one example of a method of making thecable locking assembly.

FIG. 10 Is a side view of another example of a pipe splitting assemblyincluding a plurality of cable locking assemblies.

FIG. 11 Is a perspective view of one example of an expander.

FIG. 12 Is a perspective view of one example of a pipe splitter.

FIG. 13A Is a perspective view of one example of a jack tool.

FIG. 13B Is a detailed perspective view of an end of the jack tool shownin FIG. 13A.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof, and in which is shown,by way of illustration, specific embodiments in which the invention maybe practiced. In the drawings, like numerals describe substantiallysimilar components throughout the several views. In the followingdescription, the term cable is defined to include metal cables, wirerope, or other lengths of flexible line of suitable strength to pulldevices as described below through a section of pipe. These embodimentsare described in sufficient detail to enable those skilled in the art topractice the invention. Other embodiments may be utilized andstructural, or logical changes, etc. may be made without departing fromthe scope of the present invention.

FIGS. 1A, 1B show two examples of pulling systems 100, 123. As shown inFIGS. 1A, 1B the pulling systems 100, 123 include pullers 105, 124 andpipe splitting assemblies 102. Referring now to FIG. 1A, the puller 105includes a base 106 configured to lie over a first trench 108. In oneexample, the puller 105 includes, but is not limited to, a dual capstand puller, a cylindrical puller and the like. A flexible element, forinstance cable 110, extends from the puller 105 and into the firsttrench 108 over an idler roller 111. The cable 110 extends into anexisting pipe 114. As shown in FIG. 1A, the cable 110 is threadedthrough the pipe splitting assembly 102 including a pipe splitter 116and a cable holding and releasing mechanism, such as cable lockingassembly 118. The pipe splitting assembly 102 is coupled with the cable110 and pulling forces from the puller 105 are thereby transmitted fromthe cable 110 to the pipe splitting assembly 102. The pipe splitter 116engages against the existing pipe 114 to split the existing pipe and anexpanding surface (e.g., frustoconical surface) in the pipe splitter 116pushes the broken existing pipe 114 into the surrounding soil. As shownin FIG. 1A, in one example the cable locking assembly 118 includes acoupling to connect with a replacement pipe 120. As the pipe splittingassembly 102 is drawn through the existing pipe 114 the replacement pipe120 is correspondingly drawn after the pipe splitting assembly 102 andpositioned in the original position of the existing pipe 114.

Referring again to FIG. 1A, a second trench 122 is shown. The cable 110prior to operation of the pipe splitting assembly is thread through theexisting pipe 114 to the second trench 122. In the second trench 122 thepipe splitting assembly 102 is coupled around the cable 110.Additionally, the replacement pipe 120, if included with the pipesplitting assembly 102, is coupled with the pipe splitting assembly 102.Operation of the puller 104 pulls the pipe splitting assembly 102 asdescribed above. The pipe splitting assembly 102 is drawn from thesecond trench 122 towards the first trench 108 to break the existingpipe 114 therebetween and position the replacement pipe 120.

Referring now to FIG. 1B, another example of a puller 124 is shownpositioned at a first trench 126. Puller 124, in this example, isconfigured for placement within the first trench 126 as opposed toplacement above the trench 108, as shown in FIG. 1A. In both examples,the pullers 104, 124 are configured as compact mobile units that arepositioned above or within the trenches 108, 126 by operators. Heavyequipment including hydraulic arms and the like is not needed forplacement of the pullers 104, 124 prior to their use in the trenches108, 126. Referring again to FIG. 1B, the pulling system 123 operates inmuch the same manner as the pulling system 100 shown in FIG. 1A. Thecable 110 is threaded through the existing pipe 114 to the second trench128. The cable 110 is coupled with the pipe splitting assembly 102including the pipe splitter 116 and cable locking assembly 118. The pipesplitting assembly 102 is then drawn through the existing pipe 114 wherethe pipe splitter 116 engages against the existing pipe 114 breaking theexisting pipe and expanding it outward into the surrounding soil. Asdescribed above, in one example, the cable locking assembly 118 iscoupled with a replacement pipe 120. The replacement pipe 120 is pulledbehind the pipe splitting assembly 102 during operation of the puller124 to position the replacement pipe in place of the existing pipe 114.The pullers 104, 124 are thereby able to break and expand an existingpipe 114 and at the same time pull through and position the replacementpipe 120.

Referring now to FIG. 2A an exploded view of the pipe splitting assembly102 is shown. As discussed above, the pipe splitting assembly 102includes a pipe splitter 116 and cable locking assembly 118. The pipesplitter 116 includes a cable passage 204. The cable passage 204 issized and shaped to receive a cable, such as cable 110 shown in FIGS.1A, 1B. Referring to FIG. 2B, the cable passage 204 extends from thepipe splitter proximal end 200 toward the pipe splitter distal end 202.The pipe splitter 116 includes at least one cutting surface 206configured to engage against an existing pipe, such as existing pipe114, and break the existing pipe. As shown in FIG. 2A, the example pipesplitter 116 includes two cutting surfaces 206 disposed on opposingsides of the pipe splitter 116. In another example, the pipe splitter116 includes a plurality of cutting surfaces such as three or morecutting surfaces 206. The pipe splitter distal end 202, as shown inFIGS. 2A, 2B, includes an expanding surface 203 having a taper from thedistal end 202 towards an intermediate portion 205 between the pipesplitter distal end 202 and the pipe splitter proximal end 200. Theexpanding surface 203 engages against broken existing pipe 114 (seeFIGS. 1A, 1B) and pushes the broken existing pipe into the surroundingsoil. Expansion through the expansion surface 203 provides space for thecable locking assembly 118 and pipe puller 212 as well as replacementpipe 120 to be drawn through the space and position the replacement pipe120.

Referring again to FIGS. 2A, 2B, the cable locking assembly 118 includesa cable gripping device collar 210, a cable gripping device 208 and ajack 220. The cable gripping device collar 210 in one example includes ajack receiving inner surface 223 as shown in FIG. 2A. In anotherexample, the cable gripping device collar 210 includes a cable grippingdevice receiving inner surface 218 as shown in FIG. 2B. As shown in FIG.2B, the jack 220 is placed within the cable gripping device collar 210as is the cable gripping device 208. When the cable locking assembly 118is assembled the jack 220 is positioned along the jack receiving innersurface 223 as shown in FIG. 2B, and the cable gripping device 208 ispositioned within the cable gripping device receiving inner surface 218.As shown in FIG. 2B, the jack 220 includes a jack cable passage 222 andthe cable gripping device 208 includes a cable gripping device cablepassage 225. Both of the cable passages 222, 225 are sized and shaped toreceive the cable (e.g., cable 110 shown in FIGS. 1A, 1B). As will bedescribed in further detail below, the cable gripping device 208includes a cable gripping device outer surface 216. When the cablegripping device outer surface 216 engages against the cable grippingdevice receiving inner surface 218 of the cable gripping device collar210 the cable gripping device 208 is forced to clamped around the cable,such as cable 110, and the cable gripping device 208 immobilizes thecable relative to the cable locking assembly 118. Conversely,disengagement of the cable gripping device 208 from the cable grippingdevice collar 210 releases engagement of the cable from the cablegripping device 208 thereby allowing sliding movement of the cablerelative to the cable gripping device 208 and cable gripping devicecollar 210. As will be described in further detail below, the jack 220is movable along the jack inner surface 223 of the cable gripping devicecollar 210 towards the cable gripping device 208. Engagement of the jack220 with the cable gripping device 208 when the cable gripping device islocked with the cable gripping device receiving inner surface 218 of thecable gripping device collar 210 pushes the cable gripping device 208out of engagement with the cable gripping device collar 210 therebyreleasing engagement with the cable.

Optionally, the cable locking assembly 118 includes a pipe puller 212.The pipe puller 212 is configured for coupling with a replacement pipe,such as replacement pipe 120 shown in FIGS. 1A, 1B. In one example, thepipe puller 212 is coupled with a pipe puller flange 214 of the cablegripping device collar 210. For instance, the pipe puller 212 is coupledwith the cable gripping device collar 210 with a fastener systemincluding, but not limited to, threading, pins, mechanical fittings andthe like.

When the pipe splitting assembly 102 is assembled as shown in FIG. 2Bwith the cable gripping device 208 engaged against the cable grippingdevice receiving inner surface 218 of the cable gripping device collar210 the cable is clamped by the cable gripping device 208 and therebyprevented from sliding relative to the pipe splitting assembly 102.Pulling forces transmitted through the cable are transmitted through thecable gripping device 208 to the cable gripping device collar 210. Asshown in FIG. 2B, the pipe splitter distal end 202 is coupled with thecable gripping device collar 210. When pulled, the cable gripping devicecollar 210 thereby pushes the pipe splitter 116 forward, as shown inFIGS. 1A, 1B. The pipe splitter 116 is engaged against the existing pipe114 to break and expand the existing pipe into the surrounding soilcreating sufficient space for pulling of the pipe splitting assembly 102and, in one example, pulling of a replacement pipe 120.

One example of a cable gripping device 208 is shown in FIG. 3, The cablegripping device 208 includes a proximal end 302 and a distal end 300. Inone example the cable gripping device 208 includes a plurality of cablegripping device pieces. For instance, the cable gripping device 208includes two cable gripping device pieces. In the example shown in FIG.3, the cable gripping device 208 includes three cable gripping devicepieces 304, 306, 308. The exterior of the cable gripping device pieces304, 306, 308 forms the outer cable gripping device surface 216. Asshown in FIG. 3, the outer cable gripping device surface 216 tapers fromthe distal end 300 toward the proximal end 302. Referring again to FIG.2B, the cable gripping device outer surface 216 has a correspondingshape to the cable gripping device receiving inner surface 218 of thecable gripping device collar 210. The corresponding shapes of surfaces216, 218 allows for a tight engagement between the cable gripping device208 and the cable gripping device collar 210. As the cable (e.g., cable110) shown in FIGS. 1A, 1B is drawn by a puller, the cable grippingdevice 208 which is clamped around the cable is pulled into closerengagement with the cable gripping device collar 210. The correspondingcable gripping device outer surface 216 and cable gripping devicereceiving the inner surface 218 are thereby tightly engaged. The tightengagement deforms at least one of the cable gripping device 208 and thecable gripping device receiving inner surface 218 forming a tightinterference fit between the cable gripping device 208 and cablegripping device collar 210, The interference fit between the cablegripping device 208 and cable gripping device collar 210 ensures thatthe cable is tightly clamped by the cable gripping device 208 throughoutoperation of the pulling system 100 shown in FIGS. 1A, 1B. Referringagain to FIG. 3, in one example, the cable gripping device 208 includesfrictional surface 310 along the cable gripping device cable passage225. The frictional surfaces 310 tightly grasp the cable when the cablegripping device 208 is clamped around the cable because of tightengagement with the cable gripping device collar 210 (see FIGS. 2A, 2B).

The jack 220 is shown in FIG. 4. The jack 220 extends between a jackdistal end 400 and a jack proximal end 402. As previously described, thejack 220 includes a jack cable passage 222. The jack cable passage 222allows for slidable movement of the cable 110 shown in FIGS. 1A, 1Brelative to the jack 220. The jack 220 further includes a couplingfeature 404. As shown in FIG. 4, in one example, the coupling feature404 extends around the perimeter of the jack 220. The coupling feature404 includes, but is not limited to, a threaded surface, a gearedsurface such as a helical gear surface, a rack surface, and the like. Asdescribed further below, the coupling feature 404 allows the jack 220 tomovably couple with the cable gripping device collar 210. Movement suchas a rotational movement applied to one of the jack 220 or cablegripping device collar 210 moves the jack 220 relative to the cablegripping device collar 210 toward the cable gripping device 208.Movement of the jack 220 engages a cable gripping device engagementsurface 408 of the jack 220 against the cable gripping device 208 (see,FIGS. 2A, 2B). Movement of the jack 220 relative to the cable grippingdevice collar 210 moves the jack 220 (when engaged with the cablegripping device 208) as a single unit with the cable gripping device208. The force applied to the cable gripping device 208 by the jack 220overcomes the forces seating the cable gripping device 208 with thecable gripping device receiving inner surface 218 of the cable grippingdevice collar 210. The interference fit between the cable grippingdevice 208 and cable gripping device collar 210 is thereby broken bymovement of the jack 220 acting upon the cable gripping device 208.

The jack 220 includes, in another example, a tool receiving surface 406.As shown in FIG. 4, the example jack 220 includes dual tool receivingsurfaces 406 on opposed sides of the jack 220. The tool receivingsurfaces 406 optionally receive tools such as a wrench, rachet, handtools and the like. The tools are rotated to rotate the jack 220relative to the cable gripping device collar 210.

Referring now to FIG. 5, the cable gripping device collar 210 is shown.The cable gripping device collar 210 extends between a cable grippingdevice collar proximal end 502 and a cable gripping device collar distalend 500. As previously described, the cable gripping device collar 210includes a jack receiving inner surface 223 and a cable gripping devicereceiving inner surface 218. The jack receiving surface 223 is sized andshaped to receive the jack 220 shown in FIG. 4.

Referring again to FIG. 5, the cable gripping device collar 210 includesa coupling feature 504 extending at least part way around the jackreceiving inner surface 223. The coupling features 404, 504 of the jack220 and cable gripping device collar 210 couple together to form amechanical advantage coupling 226 as shown in FIG. 2B. Coupling feature504 includes, but is not limited to, a threading surface having acorresponding fit to threading of one example of the coupling feature404, a geared surface, a rack surface and the like for engagement withthe coupling feature 404 shown with the jack 220 in FIG. 4. The couplingfeatures 404, 504 are engaged with each other so that force input 410applied to at least one of the jack 220 and the cable gripping devicecollar 210 results in translational movement of the jack 220 along thecable gripping device collar longitudinal axis 508 toward the cablegripping device 208. Further, engagement between the coupling features404, 504 at the mechanical advantage coupling 226 is configured toprovide a force output 412 at the cable gripping device engaging surface408 of the jack 220 that is greater than the force input 410, asdescribed below.

The cable gripping device receiving surface 218, as previously shown inFIG. 2B, includes a taper extending from the cable gripping devicecollar distal end 500 toward the cable gripping device collar proximalend 502. As described above, the cable gripping device receiving innersurface 218, in one example, has a corresponding geometry to the cablegripping device outer surface 216 of the cable gripping device 208. Whenthe cable gripping device 208 is fit within the cable gripping devicecollar 210 and drawn proximally toward the cable gripping device collarproximal end 502 the cable gripping device 208 tightly engages with thecable gripping device receiving inner surface 218. At least one of thecable gripping device receiving surface 218 and the cable grippingdevice outer surface 208 deforms and forms an interference fit betweenthe cable gripping device 208 and cable gripping device collar 210. Asdescribed above, this interference fit tightly engages the cablegripping device 208 around the cable (e.g., cable 110 shown in FIGS.0.1A, 1B), thereby preventing movement of the cable relative to thecable locking assembly 118. Pulling forces from the cable 110 transmitthrough the cable locking assembly 118 to the pipe splitter 116 shown inFIGS. 2A, 2B, allowing movement of the pipe splitting assembly 102relative to an existing pipe 114. The pulling forces move the pipesplitter 116 into engagement with the existing pipe 114 to break theexisting pipe and force the existing pipe into the surrounding soil tomake room for the pipe splitting assembly 102 and the replacement pipe120.

Referring again to FIG. 4 and FIG. 5, the coupling features 404 and 504of the jack 220 and cable gripping device collar 210, respectively formthe mechanical advantage coupling 226 shown in FIG. 2B. The mechanicaladvantage coupling 226 allows for a force input such as force input 410shown in FIG. 4. To move the jack 220 relative to the cable grippingdevice collar 210 along a cable gripping device collar longitudinal axis508. Movement of the jack 220 along the cable gripping device collarlongitudinal axis 508 produces a longitudinal force output 412 at thejack engaging surface 408. When the jack 220 is engaged with the cablegripping device 208 at the jack engaging surface 408 the force output412 moves the cable gripping device 208 out of engagement with the cablegripping device receiving inner surface 218 of the cable gripping devicecollar 210. Because of the mechanical advantage coupling 226 between thejack 220 and the cable gripping device collar 210 the force input 410 tothe jack 220 is multiplied resulting in the force output 412 at thecable gripping device engaging surface 408. A user is thereby able toprovide a force input 410 (e.g., through a hand tool such as a wrench)that is multiplied to produce the force output 412 at the cable grippingdevice engaging surface. The force output 412 is greater than the forceinput 410. The increased force output 412 is able to break the lockingengagement between the cable gripping device 208 and the cable grippingdevice collar 210. As shown in FIG. 5, in one example the cable grippingdevice collar 210 includes at least one tool receiving surface 506. Asshown in FIG. 2B, in another example, the cable gripping device collar210 includes dual tool receiving surfaces 506.

Where the user wishes to move the jack 220 relative to the cablegripping device collar 210 the user engages a first tool such as awrench around the jack at the tool receiving surfaces 406. The user thenengages a second tool around the cable gripping device collar 210 at thetool receiving surfaces 506 of the cable gripping device collar. Thejack 220 is rotated relative to the cable gripping device collar 210with the tool engaged at the tool receiving services 406. The cablegripping device collar is held immobile with a tool engaged at the toolreceiving surfaces 506 of the cable gripping device collar 210. Rotationof the jack 220 applies the force input 410 to the jack 220. Movement ofthe jack 220 along the cable gripping device collar 210 applies theforce output 412 through the cable gripping device engaging surface 408to the cable gripping device 208 where the jack 220 is engaged (throughlongitudinal movement along the cable gripping device collar 210) cablegripping device 208. The user is thereby able to rotate the jack 220relative to the cable gripping device collar 210 with hand tools toapply a sufficient force output 412 greater than the force input 410 todisengage the cable gripping device 208 from the cable gripping devicecollar 210 breaking the interference fit between the cable grippingdevice 208 and the cable gripping device collar 210. In one example, atleast the jack 220 and cable gripping device collar 210 are formed withmaterials having sufficient strength to receive the force input 410 andtransmit the force output 412 to the collar 208. Materials of the jack220 and cable gripping device collar 210 include, but are not limitedto, carbon steels, alloy steels and the like.

FIGS. 6 and 7 show examples of the pipe splitting assembly 102 and cablelocking assembly 118. In FIG. 6, the cable gripping device 208 is in afirst interference fit orientation and in FIG. 7 the cable grippingdevice 208 is in a second disengaged orientation where the interferencefit between the cable gripping device 208 and cable gripping devicecollar 210 is broken and the cable 110 is free to slide relative to thecable gripping device 208, collect collar 210 and jack 220.

Referring first to FIG. 6, the pipe splitting assembly 102 is shown inan assembled state where the cable gripping device 208 is clamped aroundthe cable 110. As previously described, when the cable gripping device208 is clamped around the cable 110 the cable gripping device outersurface 216 is interference fit with a cable gripping device receivinginner surface 218 of the cable gripping device collar 210. At least oneof the cable gripping device collar 210 and cable gripping device 208are deformed in this first interference fit orientation to compress thecable gripping device 208 around the cable 110 so that the cablegripping device 208 (e.g., cable gripping device pieces 304, 306, 308shown in FIG. 3) engages around the cable 110 to hold the cable immobilerelative to the cable gripping device 208 and cable gripping devicecollar 210. The jack 220 in FIG. 6 is shown in a first engagedorientation where a surface of the jack 220 such as the cable grippingdevice engaging surface 408, shown in FIG. 4, is engaged with the cablegripping device 208 (e.g., jack receiving surface 314). In this firstengaged orientation the jack 220 provides no force or an incidentalforce to the cable gripping device 208. In another example, shown inFIG. 2B, the cable gripping device 208 is not engaged with the jack 220(i.e., there is a gap between the jack 220 and the cable gripping device208). Additionally, as shown in FIG. 6, the pipe splitter 116 is coupledaround the cable 110 and engaged with the cable gripping device collar210. Because the cable gripping device collar 208 is clamped around thecable 110 pulling forces applied through the cable 110 to the cablelocking assembly 118 are transmitted through the cable gripping devicecollar 210 to the pipe splitter 116. As previously described above,pulling forces transmitted through the cable 110 thereby pull the pipesplitter 116 through an existing pipe, such as existing pipe 114 shownin FIGS. 1A, 1B.

Referring now to FIG. 7, the cable locking assembly 118 is shown in asecond disengaged orientation where the cable gripping device 208 ismovable along the cable gripping device collar longitudinal axis 508.The interference fit between the cable gripping device 208 and the cablegripping device collar 210 has been broken thereby allowing slidingmovement of the cable 110 relative to the cable gripping device 208 andcable gripping device collar 210. To access the jack 220 to break theinterference fit between the cable gripping device 208 and cablegripping device collar 210 the pipe splitter 116 is slid proximallyalong the cable 110 thereby exposing the jack proximal end 402. In oneexample, the pipe puller 212 is disengaged from the pipe puller flange214 at the cable gripping device collar distal end 500. When the jack220 is operated to disengage the cable gripping device 208 from thecable gripping device collar 210, positioning the pipe puller 212 awayfrom the cable gripping device collar 210 provides space for the cablegripping device 208 to move distally relative to the cable grippingdevice collar 210. In another example, the pipe puller 212 is coupledwith the cable gripping device collar 210 when the jack 220 is movedalong the cable gripping device collar longitudinal axis 508 todisengage the cable gripping device 208 from the cable gripping devicecollar 210.

In one example, once the pipe splitter 116 is slid away from the cablegripping device collar 210 to expose the jack proximal end 402 the jack220 is rotated relative to the cable gripping device collar 210. In yetanother example, the jack 220 is rotated relative to the cable grippingdevice collar 210 by application of a force input 410 through toolreceiving services 406 near the jack proximal end 402 (See FIGS. 4 and5). As previously described, the cable gripping device collar 210 isheld immobile relative to the jack 220, for instance, with a toolcoupled with the cable gripping device collar 210 at the tool receivingsurfaces 506. As shown in FIGS. 6 and 7, the jack 220 is coupled to thecable gripping device collar 210 with a mechanical advantage coupling226. Rotation of the jack 220, in one example, moves the jack 220 alongthe cable gripping device collar longitudinal axis 508 toward the cablegripping device 208. As previously, described the force input 410 ismultiplied by the mechanical advantage coupling 226 resulting in a forceoutput 412 (See FIG. 4) applied through the cable gripping deviceengaging surface 408 of the jack to the jack receiving surface 314 ofthe cable gripping device 208. The jack 220 and the cable grippingdevice 208 move together toward the cable gripping device collar distalend 500 along the cable gripping device collar longitudinal axis 508.The force output 412 of the jack 220 forces the cable gripping device208 out of the interference fit with the cable gripping device collar210 thereby breaking the interference fit and disengaging the cablegripping device outer surface 216 from the cable gripping devicereceiving inner surface 218 of the cable gripping device collar 210.Where the jack 220 is the second engaged position shown in FIG. 7relative to the first engaged position shown in FIG. 6. The outer cablegripping device surface 216 is unseated from the cable gripping devicereceiving inner surface 218 thereby allowing the cable gripping device208 to assume a non-compressed state and further allowing slidingmovement of the cable 110 relative to the cable gripping device and thecable gripping device collar 210, as shown in FIG. 7. For example, inthe non-compressed state the cable gripping device pieces 304, 306, 308(FIG. 3) are only incidentally engaged with the cable 110 therebyallowing the cable 110 to slide relative to the cable gripping device208, cable gripping device collar 210 and jack 220.

Once the cable gripping device 208 is disengaged from the cable 110, thepipe splitting assembly 102 is removed from the cable 110. For instance,the pipe puller 212 is slid off the cable 110 followed by removal of thecable gripping device 208, cable gripping device collar 210 and jack220. The pipe splitter 116 is subsequently slid off of the cable 110after removal of the cable locking assembly 118 and pipe puller 212. Thecable locking assembly 118, as described, allows for the tight clampingof the cable 110 by the engagement of the cable gripping device 208 withthe cable gripping device collar 210. The interference fit between thecable gripping device outer surface 216 and the cable gripping devicereceiving inner surface 218 creates a reliable clamping effect aroundthe cable 110. The pulling forces are transmitted from the cable 110 tothe pipe splitter 116 through the cable gripping device collar 210engaged with the cable gripping device 208.

The cable locking assembly 118 further provides a convenient mechanismfor disengaging the cable gripping device 208 from the cable grippingdevice collar 210. The mechanical advantage coupling 226 described aboveallows for force inputs, such as force input 410, to move the jack 220relative to the cable gripping device collar 210. The force output 412is greater than the force input 410 because of the mechanical advantagecoupling 226, and the jack 220 engages with the cable gripping device208 and moves the cable gripping device 208 by applying the force output412 to the cable gripping device 208. The jack 220 thereby breaks theinterference fit between the cable gripping device outer surface 216 andcable gripping device receiving inner surface 218 allowing for easydisassembly of the pipe splitting assembly 102. Despite the strongcoupling between the cable gripping device 208 and the cable grippingdevice collar 210, in one example, a single user with a first toolcoupled with the tool receiving surface 406 of the jack 220 and a secondtool coupled with the tool receiving surface 506 of the cable grippingdevice collar 210 is able to rotate the jack 220 relative to the cablegripping device collar 210 to disengage the collar 208 from the cablegripping device collar 210. Difficult and time consuming processes suchas hammering a cable locking mechanism to disengage a cable from a pipesplitting assembly and using power tools to disengage a cable from apipe splitting assembly and the like are thereby avoided. Instead, theuser is able to quickly and easily disengage the pipe splitting assemblyfrom the cable 110 and rapidly disassemble the pipe splitting assembly102 from the cable. In other examples the mechanical advantage coupling226 includes, but is not limited to, gears such as mechanical advantagegear assemblies, gear and rack assemblies and the like where the forceoutput, such as force output 412 is greater than the force input 410.The jack 220 is moved by the user relative to the cable gripping devicecollar 210 and engaged with the cable gripping device 208 to move thejack 220 and cable gripping device 208 together relative to the cablegripping device collar 210 to disengage the cable gripping device 208from the cable gripping device collar.

Referring now to FIG. 8, one example of a method 800 for releasing acable puller interference fit is shown. Where applicable, reference ismade to various elements of the pipe splitting assembly 102 shown inFIGS. 1A through 7, including the cable locking assembly 118. At 802, ajack 220 is moved along a cable gripping device collar 210 and over acable 110 toward a cable gripping device 208. The cable gripping device208 is clamped to the cable 110 thereby immobilizing the cable grippingdevice 208 and cable gripping device collar 210 relative to the cable.The cable gripping device 208 is locked with the cable gripping devicecollar 210 by an interference at a first locked position relative to thecable gripping device collar 210. As described above, in one example,the cable gripping device outer surface 216 is interference fit with thecable gripping device receiving inner surface 218 of the cable grippingdevice collar 210. At 804, the jack 220 is engaged against the cablegripping device 208. For instance, in one example, a cable grippingdevice engaging surface 408 of the jack 220 is engaged with a jackreceiving surface 314 of the cable gripping device 208, At 806, the jack220 and the cable gripping device 208 are moved together relative to thecable gripping device collar 210 to a second disengaged position (e.g.,see FIG. 7). Moving the jack and the cable gripping device relative tothe cable gripping device collar 210 includes breaking the interferencefit between the cable gripping device 208 and the cable gripping devicecollar 210. As described above, in one example, moving the jack 220along the cable gripping device collar 210 includes moving the jack 220relative to the cable gripping device collar 210 with a mechanicaladvantage coupling, such as the mechanical advantage coupling 226 shownin FIGS. 6 and 7. The mechanical advantage coupling 226 movably couplesthe jack 220 with the cable gripping device collar 210.

Several options for the method 800 follow. In one example, where thejack 220 and cable gripping device collar 210 are coupled together withthe mechanical advantage coupling 226, moving the jack 220 and the cablegripping device 208 together includes inputting an input force, such asforce input 410 shown in FIG. 4, to at least one of the jack 220 and thecable gripping device collar 210 (e.g., force may be input to either thejack 220 or cable gripping device collar 210 as long as one of the cablegripping device collar and jack are held immobile relative to theother). Moving the jack 220 and the cable gripping device 208 togetherfurther includes transmitting an output force, such as output force 412shown in FIG. 4, to the cable gripping device 208 from the jack 220. Theoutput force 412 is greater than the input force 410 because of themechanical advantage coupling 226. In another example, inputting theinput force 410 includes rotating at least one of the jack 220 and thecable gripping device collar 210 relative to the other of the cablegripping device collar and the jack. Further, outputting the outputforce 412 includes moving the jack 220 along a cable gripping devicelongitudinal axis, such as the axis 508 shown in FIGS. 5, 6 and 7,toward the cable gripping device 208. In yet another example, the vectorof the input force 410 is not coincident with the vector of the outputforce 412 (see respective arrows shown in FIG. 4). For instance, theforce input 410 is provided in a rotational arcuate manner and theoutput force 412 is provided in a longitudinal manner along the cablegripping device collar longitudinal axis 508.

In another example, the method 800 includes restraining lateral movementof the jack 220 relative to the cable gripping device collarlongitudinal axis 508. Lateral movement of the jack 220 is restrained byengagement of the cable gripping device collar 210 around the jack 220.For instance, the engagement of the cable gripping device collar 210around the jack 220 ensure that force input to the jack 220 results inlongitudinally movement of the jack 220 toward the cable gripping device208 (e.g., with a threaded mechanical advantage coupling, gearedmechanical advantage coupling, rack and gear mechanical advantagecoupling and the like). In still another example, the method 800 furtherincludes sliding a pipe splitter such as pipe splitter 116 proximallywhere the pipe splitter 116 is coupled with a cable gripping devicecollar proximal end 502. Sliding the pipe splitter 116 relative to thecable gripping device collar 210 reveals at least a portion of the jack220 (e.g., jack proximal end 402 having tool receiving surfaces 406).

FIG. 9 shows one example of a method 900 for making a cable lockingassembly, such as cable locking assembly 118 shown in FIGS. 2A, 2B.Where applicable reference is made to elements shown in FIG. 1A through7 of the pipe splitting assembly 102. At 902, a cable gripping devicecollar 210 is movably coupled around a cable gripping device 208. Thecable gripping device 208 is configured to clamp a cable, such as cable110, extending through the cable gripping device 208 when the cablegripping device is in locking engagement with the cable gripping devicecollar, in one example, the locking engagement includes an interferencefit between the cable gripping device 208 and the cable gripping devicecollar 210. Optionally, the cable gripping device 208 is locked with thecable gripping device collar 210 by an interference fit that immobilizesthe cable gripping device 208 and cable gripping device collar 210relative to the cable 110 and prevents longitudinal movement of thecable gripping device 208 relative to the cable gripping device collar210. At 904, a jack such as jack 220 is movably coupled with the cablegripping device collar 210. The jack 220 is movable on the cablegripping device collar 210 toward the cable gripping device 208 as shownin FIGS. 2B, 6, and 7. The jack 220 is engagable with the cable grippingdevice 208, and the jack 220 is configured to move the cable grippingdevice 208 out of locking engagement (e.g., interference fit) with thecable gripping device collar 210 to release clamping of the cable 110.As previously described, in one example, the jack 220 is movably coupledwith the cable gripping device collar 210 by a mechanical advantagecouple 226. The mechanical advantage coupling 226 allows the user toinput a force, such as force input 410 shown in FIG. 4, and generate aforce output 412 greater than the force input 410. The force output 412is transmitted to the cable gripping device 208 when it is desired touncouple the cable gripping device 208 from the cable 110 anddisassemble the pipe assembly 102 from the cable 110.

Several options for the method 900 include the following. In one examplethe method 900 includes coupling a pipe puller 212 with the cablegripping device collar 210. In another example, the cable grippingdevice collar 210, cable gripping device 208, jack 220 and a pipesplitter 116 are coupled with the cable 110 by passing the cable 110through cable passages 204, 222, 225. In yet another example, the cablegripping device 208 is coupled around the cable 110 with two or morecable gripping device pieces 304, 306, 308. For instance, the cablegripping device pieces 304, 306, 308 are held around the cable 110 withincident contact generated by an elastic band 313 held within an elasticband groove 312 extending around the cable gripping device 208 (e.g.,over the cable gripping device pieces 304, 306, 308).

Referring now to FIG. 10, another example of a pipe splitting assembly1000 is shown. The pipe splitting assembly 1000 is similar in somerespects to the pipe splitting assembly 102 described herein. The pipesplitting assembly 1000 includes a pipe splitter 1002. The pipe splitter1002 has one or more cutting surfaces 1003 sized and shaped to engagewith the inner wall of an existing pipe and break the existing pipe. Inone example, the pipe splitter 1002 includes a frusto-conical expandingsurface 1009 at the pipe splitter distal end 1026. As shown, the pipesplitter proximal end 1024 has a substantially cylindrical surface thatsurrounds the cable 1010 extending therethrough.

The pipe splitting assembly 1000 further includes, in one example, anexpander 1004 positioned near the pipe splitter distal end 1026. Thecable 1010 extends through the expander 1004 to the cable distal end1012. The expander 1004 includes an expanding surface 1011 near theexpander proximal end 1028. In one example, the expander 1004 includes asubstantially cylindrical surface near the expander distal end 1030.

As shown in FIG. 10, each of the pipe splitter 1002 and the expander1004 includes a first cable locking assembly 1005 and a second cablelocking assembly 1007, respectively. The first cable locking assembly1005 includes a first cable gripping device 1006 (shown in phantomlines) that is similar in at least some respects to the cable grippingdevice 208 shown in FIGS. 2A, B. The first cable gripping device 1006 isengaged against a first gripping device receiving surface 1020 extendingalong an inner surface of the pipe splitter 1002. The first grippingdevice 1006 and the first gripping device receiving surface 1020 havecomplementary geometries that facilitate fitting of the first grippingdevice 1006 within the first gripping device receiving surface 1020.Tight engagement between the first gripping device 1006 and the firstgripping device receiving surface 1020 locks the first gripping device1006 to the pipe splitter 1002 and locks the first gripping device tothe cable 1010 thereby preventing movement of the cable relative to thepipe splitter 1002.

In a similar manner, the expander 1004 includes a second cable lockingassembly 1007 having a second cable gripping device 1008. The secondcable gripping device 1008 is sized and shaped to fit within theexpander 1004 along the second gripping device receiving surface 1022.Tight engagement between the second cable gripping device 1008 and thesecond cable gripping device receiving surface 1022 locks the secondcable gripping device 1008 around the cable 1010 and immobilizes thecable 1010 relative to the expander 1004.

Each of the first and second cable locking assembly examples 1005, 1007shown in FIG. 10 includes a jack opening (e.g., first and second jackopenings 1016, 1018). The first and second jack openings 1016, 1018 aresized and shaped to receive an end of a jack tool, such as jack tool1014 shown in FIG. 10, and further shown in FIGS. 13A, B. A jackengagement surface of the jack tool 1014 is configured to engage withthe cable gripping devices 1006, 1008 when inserted through the openings1016, 1018. Jack tool movement along the direction shown at 1032 engagesthe jack engagement surface with the cable gripping devices 1006, 1008and disengages the cable gripping devices from the first and secondgripping device receiving surfaces 1020, 1022. Disengagement of thefirst and second cable gripping devices 1006, 1008 from the receivingsurfaces 1020, 1022 allows the cable 1010 to slide relative to the pipesplitter 1002 and the expander 1004 allowing disassembly of the pipesplitting assembly 1000 without difficult and time-consuming effort bythe user to otherwise break the engagements.

One example of the expander 1004 is shown in FIG. 11. As previouslydescribed, the expander 1004 has a frusto-conical shape that tapers fromthe expander distal end 1030 toward the expander proximal end 1028. Thesecond jack opening 1018 is shown in FIG. 11. Referring now to FIG. 12,one example of the pipe splitter 1002 is shown. The pipe splitter 1002includes the first jack opening 1016. As described above, the jackopenings 1016, 1018 allow access to the first and second cable grippingdevices 1006, 1008 of the first and second cable locking assemblies1005, 1007. The jack tool 1014 (FIG. 10) is fit through the openings1016, 1018 to engage with and decouple the first and second cablegripping device 1006, 1008 from their respective first and secondgripping device receiving surfaces 1020, 1022 (also shown in FIG. 10).

Referring now to FIGS. 11 and 12, the surfaces of the pipe splitter 1002and the expander 1004 surrounding the openings 1016, 1018 are shown ingreater detail. In one example, the openings 1016, 1018 have roundedends, such as first and second fulcrum rests 1200, 1100 sized and shapedto receive the fulcrum of the jack tool 1014 (described below). Therounded configuration of the first and second fulcrum rests 1200, 1100guides the jack tool 1014 during movement through the openings 1016,1018 (shown in FIG. 10 by arrow 1032). The fulcrum rests 1100, 1200direct the disengaging force transmitted by the jack tool 1014 along apipe splitting assembly longitudinal axis 1013 into the first and secondcable gripping devices 1006, 1008 without any component of force beingdirected away from the axis 1013. The full force supplied by mechanicaladvantage of the jack tool 1014 is thereby applied to cable grippingdevices 1006, 1008 to more easily cause disengagement. Each of the firstand second jack openings 1016, 1018 further includes a first and secondjack opening travel distance 1202, 1102. The travel distances 1202, 1102are configured to allow the jack tool 1014 to travel during rotation anddisengage the first and second cable gripping devices 1006, 1008 fromtheir respective receiving surfaces 1020, 1022.

Optionally, the pipe splitter 1002 and the expander 1004 include a firstjack opening plug 1204 and a second jack opening plug 1104 sized andshaped to fit within the respective jack openings 1016, 1018. The plugs1204, 1104 fill the openings and prevent the ingress of foreign materialwithin the pipe splitting assembly 1000. For example, dirt, sludge andthe like is substantially prevented from infiltrating the expander 1004or pipe splitter 1002 preventing interference with the disengagement ofthe first and second cable gripping devices 1006, 1008 from the firstand second gripping device receiving surfaces 1020, 1022. That is tosay, the interior of the pipe splitter 1002 and expander 1004 are notfilled with foreign matter that could interfere with rotation of thejack tool 1014. When the plugs 1204, 1104 are disposed within the firstand second jack openings 1016, 1018, in one example, the plugs provide aflush surface to the pipe splitter and expander. Optionally, the plugsare constructed with the same or similar materials to the pipe splitter1002 and expander 1004 (e.g., steel, cast iron and the like). In anotheroption, the plugs 1204, 1104 are constructed with softer materials toassist with the removal of the plugs by deformation with a tool such asa screw driver. Such materials include, but are not limited to,composites, plastics, rubber and the like.

One example of the jack tool 1014 is shown in FIGS. 13A, B. FIG. 13Bshows a detailed view of one jack tool end 1301. Referring to FIG. 13A,the jack tool 1014 includes a handle 1306. In the example shown, thejack tool 1014 includes jack engagement surfaces 1300 at one or both ofthe jack tool ends 1301. The jack engagement surfaces 1300, in oneexample, are substantially planar for flat engagement with the first andsecond cable gripping devices 1006, 1008. The flat engagement assistswith directing disengagement forces along the pipe splitting assemblyaxis 1013 without components of force being directed away from the axisto lessen the disengagement forces. The jack tool 1014 further includesa jack fulcrum 1302 sized and shaped to engage with the fulcrum rests1100, 1200 shown in FIGS. 11 and 12. Referring to FIGS. 13A, B, the jackfulcrum 1302 has a similar geometry to the fulcrum rests 1100, 1200 tocreate a joint 1034 (FIG. 10) between the jack tool 1014 and the fulcrumrests 1100, 1200. The rounded configuration of the fulcrum rests 1100,1200 and the jack fulcrum 1302 guides the movement of the jack tool 1014during rotation and assists in directing disengagement forces fully intothe first and second cable gripping devices 1006, 1008.

In yet another example, the jack tool 1014 includes at least one jackelbow 1304 near the jack engagement surface 1300. As shown in FIGS. 13A,B, the jack elbow 1304, in one example is a scalloped portion of thejack tool 1014. The jack elbow 1304 allows the jack engagement surface1300 to hook beneath the first and second gripping device receivingsurfaces 1020, 1022 and allows the surface 1300 to engage with the firstand second cable gripping devices 1006, 1008 without interference.

The above described pipe splitting assembly 1000 with the first andsecond cable locking assemblies 1005, 1007 allows for quick and easydisengagement of the pipe splitting assembly 1000 from the cable 1010. Auser inserts the jack tool 1014 into at least one of the first andsecond jack openings 1016, 1018 and rotates the jack tool 1014 in thedirection 1032. The jack tool 1014 rotates around the joint 1034 and thejack engagement surface 1300 engages with one of the first and secondcable gripping devices 1006, 1008 and pushes the device out of lockingengagement with the corresponding first or second gripping devicereceiving surface 1020, 1022. The mechanical advantage provided by thejack tool 1014 rotated at the fulcrum rests 1100, 1200 easily transmitsenough force to break the locking engagement therebetween. The user doesnot thereby need heavy equipment or time consuming labor to break theengagement and disassemble the pipe splitting assembly 1000.

CONCLUSION

The pipe splitting assembly including the cable locking assemblydescribed herein provides a strong coupling between a puller cable andthe pipe splitting assembly, while allowing quick disengagement of thepipe splitting assembly from the cable locking assembly. The cablegripping device engages around the cable because of the interference fitbetween the cable gripping device and the cable gripping device collar.The tight interference fit locks the cable gripping device with thecable gripping device collar and thereby compresses the cable grippingdevice around the cable immobilizing the pipe splitting assembly alongthe cable for operation of a motorized puller.

The jack is movably coupled with the cable gripping device collar andengages with the cable gripping device when moved within the cablegripping device collar. The jack pushes the cable gripping device out ofengagement with the cable gripping device collar to break the lockinginterference fit between the cable gripping device and the cablegripping device collar. The cable locking assembly is thereby able totightly engage with the cable and provide reliable immobilization of thepipe splitting assembly along the cable while providing a mechanism thatquickly releases the tight engagement between the cable and the cablelocking assembly. Further, because the jack is coupled with the cablegripping device collar with a mechanical advantage coupling the userprovides a force input that is multiplied as a force output to the cablegripping device. Because of the mechanical advantage coupling, a singleuser is able to disengage the locked cable gripping device from thecable gripping device collar with hand tools, such as wrenches. Powertools including air ratchets, hammers and the like are therebyunnecessary.

Moreover, the jack is a compact device fully contained within the pipesplitting assembly. As shown, the jack is slidably coupled around thecable and moveably coupled within the cable gripping device collar. Thejack is positioned within the cylindrical perimeter of the pipesplitting assembly and does not provide a bulky mechanism that extendsoutside of the assembly that could interfere with the pipe splittingoperation.

While a number of advantages of embodiments of the invention aredescribed, the above lists are not intended to be exhaustive. Althoughspecific embodiments have been illustrated and described herein, it willbe appreciated by those of ordinary skill in the art that anyarrangement which is calculated to achieve the same purpose may besubstituted for the specific embodiment shown. This application isintended to cover any adaptations or variations of the presentinvention. It is to be understood that the above description is intendedto be illustrative, and not restrictive. Combinations of the aboveembodiments, and other embodiments will be apparent to those of skill inthe art upon reviewing the above description. The scope of the inventionincludes any other applications in which the above structures andmethods are used. The scope of the invention should be determined withreference to the appended claims, along with the full scope ofequivalents to which such claims are entitled.

I claim:
 1. A pipe splitting assembly, comprising: a pipe splitter body,including a cable passageway in a proximal end of pipe splitter body;one or more tapered cable gripping pieces mating with a tapered innersurface of the pipe splitter body; and an opening different from thecable passageway in a lateral side of the pipe splitter body to accept atool, wherein the opening exposes an end of the one or more taperedcable gripping pieces.
 2. The pipe splitting assembly of claim 1,wherein the end of the one or more tapered cable gripping pieces is aproximal end, and the opening exposes the proximal end of the one ormore tapered cable gripping pieces.
 3. The pipe splitting assembly ofclaim 1, wherein the cable passageway passes through the pipe splitterbody from the proximal end to a distal end of the pipe splitter body. 4.The pipe splitting assembly of claim 1, further including one or morecutting surfaces on a lateral surface of the pipe splitter body.
 5. Thepipe splitting assembly of claim 1, further including a plug shaped tofit in the opening.
 6. The pipe splitting assembly of claim 1, whereinthe opening includes a rounded fulcrum rest.
 7. A pipe splittingassembly, comprising: a pipe splitter body, including a cable passagewayin a proximal end of pipe splitter body; one or more tapered cablegripping pieces mating with a tapered inner surface of the pipe splitterbody; a first opening different from the cable passageway in a side ofthe pipe splitter body to accept a tool, wherein the first openingexposes an end of the one or more tapered cable gripping pieces; and apipe puller coupled behind the pipe splitter body, wherein the pipepuller is flexibly coupled to the pipe splitter body.
 8. The pipesplitting assembly of claim 7, wherein the pipe puller includes a secondopening in a side of the pipe puller to accept a tool.
 9. The pipesplitting assembly of claim 8, wherein the end of the one or moretapered cable gripping pieces is a proximal end, and the opening exposesthe proximal end of the one or more tapered cable gripping pieces. 10.The pipe splitting assembly of claim 7, wherein the cable passagewaypasses through the pipe splitter body from the proximal end to a distalend of the pipe splitter body, and wherein the pipe puller includes oneor more tapered cable gripping pieces mating with a tapered innersurface of the pipe puller.
 11. The pipe splitting assembly of claim 7,further including one or more cutting surfaces on a lateral surface ofthe pipe splitter body.
 12. The pipe splitting assembly of claim 7,further including a plug shaped to fit in first opening.
 13. The pipesplitting assembly of claim 7, further including a plug shaped to fit ina second opening.
 14. The pipe splitting assembly of claim 7, whereinthe first opening includes a rounded fulcrum rest.
 15. The pipesplitting assembly of claim 8, wherein the second opening includes arounded fulcrum rest.